1. Field of the Invention
The present invention relates to a plant operation data monitoring apparatus for detecting an error by monitoring plant data.
2. Related Art
In order to detect a plant error in a power plant, a point (sensor value) to be monitored is specified in advance and the presence or absence of a plant error is determined by comparing a specified fixed upper/lower limit and most recent plant data to see whether the limit is exceeded (see Japanese Patent Laid-Open No. 05-120582). Further, a technique has been introduced, which the limit is calculated by using an average value, a standard deviation and the like of historical plant data in a monitoring point to improve the accuracy of detecting a plant error (see Japanese Patent Application No. 2004-346716).
Unfortunately, according to the aforementioned prior art, when a plant operating state (activating, loading up, terminating, or the like) is changed, a value at a monitoring point may exceed the upper/lower limit to be used to detect a plant error in spite of a normal operation state, and an operator may be informed of a false alarm.
Therefore, there is a problem in that it takes knowledge of a skilled plant operator to determine an optimum upper/lower limit, or it takes time and efforts such as repeating a plant test operation and changing limit values many times.